Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya (million years ago), to the beginning of the Permian Period, about 299.0 ± 0.8 Mya (ICS, 2004 chart).
The Carboniferous was a time of glaciation, low sea level and mountain building, diversification and extinction; a minor marine and terrestrial extinction event among animals and plants (Carboniferous Rainforest Collapse) occurred in the middle of the period caused by climate change.
The name comes from the Latin word for coal, carbo. Carboniferous means "coal-bearing". Many coal beds were laid down globally during this period, hence the name.